If a player has an invalid decklist (missing runes) that is discovered during a deck check after the match has already finished, should they receive a game loss for that completed match?

Ruling: An illegal decklist is a game loss. If it's discovered between rounds (after a match has finished), the game loss is applied to the next round, not to the already-completed match.

Nuances:

• Once a match has finished, it's unlikely for a game loss to be applied to that match
• If someone other than the player notices the illegal decklist after the game starts, it's a game loss
• The specific penalty may be at the head judge's discretion